I've heard that some jurisdictions are planning on eliminating, if not allowing citizens to revise, the sex field on documents like passports and drivers licenses. I'm just wondering why it's listed in the first place and whether there are any actual reasons for why they should continue to be listed.
There is no absolute reason why sex has to be listed on an identity document.
The fields that are sometimes found on identity documents are those that most people can easily give, don't frequently change and differ from person to person.
So most (not all) people are assigned a name at, or close to birth. The date of birth is known for most (not all) people. Most (not all) people have little difficulty answering the question "What's your name and birth date?" And likewise, the sex of most (not all) people is easily assigned at or near birth and most (not all) people have little difficulty answering the question "Male or Female?".
Moreover, these three pieces of information change only once or twice in their life, if at all, for most people.
It is hard to think of other qualities that have these three properties of universality and fixedness that the classic Name, Sex, DoB have.
Having the "sex" information on the ID card might help identify identity theft. That would hold true especially when the name is ambiguous or uni-sex. Some examples:
Karl Maria (von Weber) - German name
Jean-Marie - French first name for a man
Marie-Jean - French name for girl (if I am not mistaken)
Eddie - unisex name (diminutive) in English
Sasha - diminutive of Alexander, Alexandra, Aleksey...
Now if you would see a major discrepancy between the person and the info on the card, you would be more likely to be cautious about dealing with that person. Equally useful for police and any other authority.
Maybe less relevant, but still possible occasionally, parents are quite creative when choosing their baby's names. Example: in the movie "Stargate Atlantis", Rodney's full name is "Meredith Rodney McKay". If you would not see the person, would you know their "sex"?
I had a colleague in school (a long time ago), and before we saw "them", we knew their name + first name (without knowing which is which). We could not decide if we would have a new girl colleague or a new male colleague. Everything was clarified when HE presented HIMelf for the classes. The family name was typical for a girl's name, and the first name was typical for a man's. So for cases like this, the information of "sex" can be very helpful.
I have a typical male's name in my country. However, when dealing with people from other countries / cultures, just looking at my name they expected to meet a girl. In one of the situations, I was even assigned a sleeping place in a girl's room - and that was fixed quickly when they saw me the first time.
Honestly I feel the real answer is human nature and inertia.
There are existing answers about sex being used as a static distinguishing value and that it might help with identity theft already, but I feel they are more post-hoc justifications more then the real motivation behind the decision, as demonstrated by all the potential counter arguments to those justifications. There are other potential better unique identifiers, and plenty of people don't look like their sex so you face plenty of 'false positives' if you are trying to identify someone by guessing if they match sex.
The true answer is long ago someone picked sex as an identifier because humans are use to using sex that way and now were just stuck going along with it. Back when we started using sex as an identifier most people weren't aware of gender/sex distinction of that non binary sexes existed. I suppose you could say it seemed like a good idea at the time.
And now everyone is using it. We've written programs that expect sex to exist to distinguish between people. Plenty of code has foolishly hard coded expectations of human nature around sex even, I have seen code that presumed only a female's last name would change before! It's habit to use sex this way, in fact it's more then habit, it feels 'right' to most people.
The fact of the mater is we naturally think of sex as a logical division of people; We've been doing that since before ID cards or even written language existed. It's a (seemingly...) easy thing to define and use, it feels 'right', and while there are some legitimate situations where its less then ideal they tend to be the minority case. Most people just want to stick with what worked in the past and they are use to.
An idealized system might use some other identifiers that better distinguish you as a person, maybe some UUID that can be publicly used - there are issues with public UUID and how their usually used/abused, I could think of ways to mitigate them, but lets not go down that rabbit hole right now. The point is a better system could be imagined, the problem is that convincing people to switch to it, to stop doing what they are use to and fight inertia, all to fix an issue that only affects a small minority of those using the ID is hard.
To give an analogy the USA would have a much easier time if they used the metric system everywhere rather then our completely random "how many inches are in a mile again?" system of measurement. However, the expense and difficulty of converting to a metric system now that everyone is use to our current system is just so high we likely will never switch, even if it theoretically would be better if we used a metric system.
In the same way your just not going to convince people to not use sex as a distinguisher regardless of it's possible negatives. It's just what everyone knows and takes for granted 'should' be on an ID card.
The purpose of most identification cards is to have a readily available and easy to use means to know who someone is from a legal perspective. As such there are a few hard requirements:
- The person's identity - typically this is a name but there are many John Smith's so that's not enough, typically date of birth is included as well to minimize duplications though that does not suffice either.
- The legal jurisdiction in question - ie is this identity defined according to and in Australia or Texas or The USA?
- Physical traits that could be used to relate the person claiming to be identified the card with the identity named in the card.
The first two are straight forward enough, the topic you'r querying seems to lie is in the third area. Some physical traits are readily changed - hair length, while others are very difficult to meaningfully change - height. Some traits where once considered very difficult to change but now are readily changed - eg eye color.
You asked specifically about sex. Sex is often identifiable quickly and while this has never been universally true, in the time since driver's licenses and passports were first created it has been largely true. As an counter example, I'm a cis-male but in some photos of me when I was a teenager you might guess I'm female. As such, much like eye color, sex is a pretty good trait for recognizing someone but is not very reliable and is currently a social hot topic.
The more physical traits you list on an identity card, the more reliable a connection can be made.
Some traits like finger prints, retina patterns, and hand geometry are exceedingly difficult to fake and as such are included directly or indirectly on higher security identification systems such as the Global Entry trusted traveller program.
It is (generally) a visibly identifiable characteristic that helps to identify a person.
Before I continue, yes, I recognize this is not 100% accurate, some people are androgenous, some people take efforts to look like members of the opposite sex (whether because they are transgender or simply because they feel like it), etc. It is not 100% perfect, but neither is any other identifying characteristic on your ID card; you can always dye your hair, wear color contacts, gain/lose weight, change your address, change your signature, etc. Nothing on your ID card is 100% guaranteed accurate all the time, but your "identifying characteristics" are things which, taken together, should largely remain verifiable and unchanged, with high probability.
Consider, for a moment, "white, woman, blonde hair, mid-30s". That paints a picture in your mind. If I showed you a picture of, say, Al Pacino, you could pretty readily tell me that this person does not match that description. Even if I showed you a picture of Leonardo DiCaprio, as he appeared in the movie Titanic, you could assess that this is probably not the right person. Now, it's certainly possible that picture of Leonardo is a woman with short hair and "manly" facial features, but it would at least raise a suspicion in your mind, and that's intentional, by design. If a legal officer (police, social services, what have you) sees someone who looks like Leonardo DiCaprio who is supposed to be a female, that person should be suspicious that this person may be committing identity fraud, even if it turns out to be a case of androgenity (is that a word?) in the end.
As a caveat, in order to accept the above explanation, you have to accept the premise that identity theft (and other forms of theft as well; for example, in the case of a driver's license, the police can cross-reference the owner of a vehicle against the person driving it to detect cases of Grand Theft Auto) is a larger problem than someone who is androgenous or cross-gender (I don't know the actual term for this; I mean someone who, for any reason, wants to look like the opposite gender, including but not limited to trans people) being "unduly questioned" due to not appearing as their identification says they should. The latter issue is attempted to be alleviated by also having a photo on the identification record but is also imperfect, for much the same reasons. If you do not accept that premise, then this answer is not going to be acceptable to you, and that's ok.
I'm just wondering why it's listed in the first place
Tradition. Documents bound to a person's identity originally did not have photographs, fingerprints, etc. Instead, they bore a written description of the person including physical characteristics such as height, weight, eye color, hair color, shape of face, "distinguishing marks" (scars, moles, that sort of thing) and, indeed, sex (as it was called in those days). Not every document had all of these, of course. As photographs became more common and eventually ubiquitous, many of these items have fallen by the wayside, and different jurisdictions and different authorities have dropped different items at different times.
There are histories when foreigners that recently acquired a citizenship in Russia have been mobilized to fight in the ongoing war. Some of these were women, but the name and family name were such that this has not been immediately seen. This explains why the government needs to know the gender of the citizen, and if some database simply contains all information that is in the passport, makes sense to include it as well.
My US passport and my Texas driver's license both specify my gender / sex (the terms are interchangeable so long as the choices are male or female, and nothing else). Other people's country may vary.
The answer to the question involves law enforcement as eyewitness observations of criminal activities oftentimes involve a gender identification (even if incorrect), and social / bureaucratic inertia as the card has always contained that information; so why change it? And finally, there's religion. Multiple religious organizations say men are men and women are women; there is no crossover (even though there is).
Eyewitness reports while oftentimes dubious, occasionally are helpful. In the cases where gender is consistently reported, that the suspect is consistently identified as male or female can aid in law enforcement investigations. Law enforcement is strongly against removing that information from ID cards.
This might just be bureaucratic inertia. The information has always been there in jurisdictions that report gender on some sort of ID card. Changing bureaucratic inertia is non-trivial due in part to "that's how it has always been" attitudes.
Finally, in many countries there is a religion-based backlash against removing such information. The US is a good example, but there are many other examples. Various political organizations explicitly ignore the huge amount of scientific research that indicates that gender identity is not as solid as people think. Per these organizations, men are men and are necessarily attracted to women, while women are women and are necessarily attracted to men. Any in-betweens are religiously forbidden by the advocates of this very strong split, scientific research be damned.
Sex has tended to be regarded as one of the fundamental overt attributes of the person.
It's inclusion on identity documents like passports - or what have become ersatz identity documents like driver's licences - is for similar reasons that age or (especially nowadays) photographs are included, namely to help verify on the spot the correspondence between the document and the bearer.
The sex correspondence can usually be assessed through voice characteristics, body size, their general bearing and manner, and so on.
Obviously, in terms of "passing off" or inappropriate use of someone else's identity document, having the sex indication alone on the document excludes about 50% of potential donors (including, traditionally, the person's marriage partner). An age indication excludes perhaps even more than 50%.
It is not always the determined fraudster planning ahead who needs to be deterred, but the person who might casually and impulsively offer a false document if there were no barrier at all - such as a son using his father's driving licence (if no age were recorded), or a wife using her husband's driving licence (if his name alone were sufficiently ambiguous as to sex).